Noted and influential MMA oddsmaker Joey Oddessa has set an opening “Odessa line” with Henderson at -340 and Diaz at +260, which makes the champ an approximate 3-to-1 favorite.

Henderson, who defended his belt for the first time with a narrow split-decision victory over ex-champ Frankie Edgar this past weekend at UFC 150, returns Dec. 8 for his network-televised main event with Diaz. The challenger earned his title shot with three consecutive victories, including a decision win over Donald Cerrone and then a submission victory over Jim Miller earlier this year in the UFC on FOX 3 headliner.

Oddessa, though, points to the Cerrone fight as a possible reason people are overvaluing Diaz.

“If Nate Diaz and Donald Cerrone didn’t have a gentleman’s agreement to stand and bang, Diaz wouldn’t be fighting Henderson at UFC on FOX 5,” Oddessa, who can be found on Twitter at @mmaodds, told MMAjunkie.com. “I think Cerrone hurt him in the first round and decided not to pursue finishing him on the ground. That was his downfall.”

Diaz, though, has the conditioning for deeper rounds, and his constant barrage of punches should present a unique challenge to Henderson.

Gustafsson, MacDonald also favorites

Oddessa has also opened lines for UFC on FOX 5’s other two big matchups.

Gustafsson (14-1 MMA, 6-1 UFC) has won six straight while Rua (21-6 MMA, 5-4 UFC) has alternated between wins and losses over his past six fights.

“After Rua’s last performance, I’m hard pressed to make him a favorite against anybody at the top of 205,” Oddessa said.

Additionally, after their bout was scratched from UFC 152 and rebooked for UFC on FOX 5, fast-rising welterweight prospect Rory MacDonald (-285) is a nearly 3-to-1 favorite over former two-division champ B.J. Penn (+225).

MacDonald (13-1 MMA, 4-1 UFC), who’s won three straight fights since a loss to now-interim champ Carlos Condit, suffered a cut in training that required 38 stitches, and his bout with Penn (16-8-2 MMA, 12-7-2 UFC) was postponed three months.

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